Re: [PATCH v3 7/8] perf python: Switch module to linking libraries from building source

From: Namhyung Kim <namhyung@kernel.org>
To: Ian Rogers <irogers@google.com>
Cc: "Peter Zijlstra" <peterz@infradead.org>,
	"Ingo Molnar" <mingo@redhat.com>,
	"Arnaldo Carvalho de Melo" <acme@kernel.org>,
	"Mark Rutland" <mark.rutland@arm.com>,
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	"Adrian Hunter" <adrian.hunter@intel.com>,
	"Kan Liang" <kan.liang@linux.intel.com>,
	"John Garry" <john.g.garry@oracle.com>,
	"Will Deacon" <will@kernel.org>,
	"James Clark" <james.clark@arm.com>,
	"Mike Leach" <mike.leach@linaro.org>,
	"Leo Yan" <leo.yan@linux.dev>, "Guo Ren" <guoren@kernel.org>,
	"Paul Walmsley" <paul.walmsley@sifive.com>,
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Subject: Re: [PATCH v3 7/8] perf python: Switch module to linking libraries from building source
Date: Mon, 24 Jun 2024 15:26:19 -0700	[thread overview]
Message-ID: <Znnyi2IPC79jMd9y@google.com> (raw)
In-Reply-To: <20240613233122.3564730-8-irogers@google.com>

On Thu, Jun 13, 2024 at 04:31:21PM -0700, Ian Rogers wrote:
> setup.py was building most perf sources causing setup.py to mimic the
> Makefile logic as well as flex/bison code to be stubbed out, due to
> complexity building. By using libraries fewer functions are stubbed
> out, the build is faster and the Makefile logic is reused which should
> simplify updating. The libraries are passed through LDFLAGS to avoid
> complexity in python.
> 
> Force the -fPIC flag for libbpf.a to ensure it is suitable for linking
> into the perf python module.
> 
> Signed-off-by: Ian Rogers <irogers@google.com>
> Reviewed-by: James Clark <james.clark@arm.com>
> ---
>  tools/perf/Makefile.config |   5 +
>  tools/perf/Makefile.perf   |   6 +-
>  tools/perf/util/python.c   | 271 ++++++++++++++-----------------------
>  tools/perf/util/setup.py   |  33 +----
>  4 files changed, 110 insertions(+), 205 deletions(-)
> 
> diff --git a/tools/perf/Makefile.config b/tools/perf/Makefile.config
> index 7f1e016a9253..639be696f597 100644
> --- a/tools/perf/Makefile.config
> +++ b/tools/perf/Makefile.config
> @@ -910,6 +910,11 @@ else
>           endif
>           CFLAGS += -DHAVE_LIBPYTHON_SUPPORT
>           $(call detected,CONFIG_LIBPYTHON)
> +	 ifeq ($(filter -fPIC,$(CFLAGS)),)

Nitpick: mixed TAB and SPACEs.

> +           # Building a shared library requires position independent code.
> +           CFLAGS += -fPIC
> +           CXXFLAGS += -fPIC
> +         endif

I'm curious if it's ok for static libraries too..

Thanks,
Namhyung

>        endif
>      endif
>    endif